I just changed out my heater blower motor resistor because the blower would only work on high speed. Took a pic of where it is located directly behind the glove box if it helps anyone. To remove the glove box remove the small plastic arm on the right side of the glove box them pull the glove box off the two hinges on each side. The resistor is then visible, remove the wiring harness and unscrew the two torque screws to remove it.
I stopped by the Jeep dealer near me and they had one in stock for about $13 so I picked it up. Cheap enough and I wanted to do it that night because I was having people in my car. Online is about $6 + shipping.